Lamp socket



May 27, 1930.

vii-mi M. CLARK LAMP SOCKET Filed Dec. 27, 1928 INVENTOR Meredz'zfi Clark ATTORN EY Patented/ May 27, i i

MEREDITH CLARK OI HEMFSTEL'D, NEW YORK LAMP SOCKET Application filed December 27, 1928. Serial No. 828,783.

The invention relates to devices for preventing accidental or unintended unscrewing or loosening of the threaded bases of incandescent lamps, plugs, and the like in their sockets Devices of this character have commonly been spring friction devices which themselves become unreliable due to time and wear, and

to other causes which tend to deform the same.

It is an object of the present invention to provide positive means for preventing the undesired displacement of the lamp or other device in its socket; and, in its preferred form, it is a feature of the invention that the opposed central contacts of the lamp base and I socket are themselves constituted to provide the positive look.

In such preferred form of the invention the central contacts constitute opposed lock ing elements, each formed with a shoulder or tooth thereon and an inclined surface leading to the top of such shoulder ortooth at one side thereof. The socket shell, as a unit with the lamp base, is resiliently yieldable to have an axial translatory movement with respect' to the central contact in the socket-shell support. When the lamp base has been screwed nearly home, inclined surfaces engage'one another, and the socket-shell and lamp base yield with respect to the socket support until the locking elements snap together ina position in which the opposed shoulders will abut to frustrate any accidental unscrewing action due to vibration or other cause. To remove the lamp or plug the same is given a pull to disengage and-clear the shoulders or teeth, after which it is unscrewed as usual.

Other objects and features of the invention will presently appear upon reference to the accompanying drawings, in which,

Fig. 1- is, a view in vertical cross section, taken on the line 11 of Fig. 3, through the 5 socket, and showing-the lamp Joase as having been screwed therein until the-socket has-been sprung out by engagement of the'inclined surfaces of the central contacts just preliminary to the locking action.

Fig. -2 is a view similar to that of Fig. 1,

into locked position.

Fig. 3 is a view in horizontal cross section of the socket, taken on the line 33 of Fig.

1, with the lamp removed.

Fig. 4 is a perspective view of the socket.

Referring to the drawings, the socket piece 1 is shown as having the usual fixed outer shell 2 and an inner threaded shell '3. This inner shell, instead ofibeing rigid with the socket piece 1, as is usual, has a spring connection therewith which permits of a limited vertical movementof the threaiied shellwith respect to the socket piece 1. This spring connection is provided by the leaf springs 4 and 5, each of which, at one end connects to and is integral with the threaded shell 3, and at its other end is attached to the insulation of the socket iece. The spring 5 is shown as having a xed screw'or rivet connection at 6 to the socket piece, where the spring a, which also serves as an electrical contact, is secured to the socket by the binding post 7, comprising an adjustable or movable screw. In Fig. 2 one of the leads 8 is shown as connected to this binding post.

iFor limiting the possible spring displacement of the threaded shell 3 with respect to the socket piece 1, there is turned down out ofeach of the leaf springs 4 and 5, at or near the point of attachmentof such spring with the socket pie cs1, and ear 9. These cars at their lower ends are bent in the form of outwardly projecting hooks 10. Cut in the threaded shell 3' opposite'the hooks, 10 are vertically disposed slots 11 through which the hooks extend. The hooked ears 9 thus serve to limit any downward movement of the threaded shell, to a distance determined by the length of the-slots 11.v

A lamp 12 is shown as having the usual threaded lamp-base, 13. In Figs. 1 and 2 the lamp is shown as threaded to difl'erent extents into the socket shell 3. On the lampbase 13 is a central contactl i for engagement with the centralcontact 15 on the socket piece 1. A lead 16is shown as connecting with the binding post of the contact 15. The opposing faces of the contacts 14 and 15 instead of shell 3, and thus to being flat, are cut to form complementary locking members, each having a shoulder'ol been screwed home, accidental unscrewing of the lamp is impossible.

The rear portions of the teeth 17 are formed with inclined surfaces as indicated at 18, and

it is these inclined surfaces which first meet as the central contacts 14 and 15 come together when the lamp is being screwed into the socket shell 3, as shown in Fig.- 1. As the inclined surfaces 18 are forcedover-each other, the leaf s rings 4 and 5 yield to permit a movement of t e threaded shell 3 away from the socket piece 1 commensurate with the pitch of inclination of the surfaces 18. After the passage of one inclined surface over the other is completed, the leaf springs 4 and 5 then act to retract the shell 3 to thesocket piece 1 and into the'position' shown in Fig.- 2 where the opposed teeth 17 prevent loosening of the lamp in the socket.

To remove the lamp from the socket, the lamp is pulled bodily down, a ainst the action of the leaf sprmgs 4 an 5, until the teeth 17 are clear of each other, and while the lamp is thus being drawn upon it is given a rotary turn to cause the teeth to clear each other laterally The lamp being thus unlocked it may then be released to the action of the leaf s rings 4 and 5, and the removal thenceforth e accomplished bymere con-. tinued rotary movement of the lamp. Although the slots 11 .in the threaded shell 3 are to pefmit the downward movement of the shell with respect to the socket piece 1,.both inthe locking and unlocking of the lamp, the hooked ears 9 function mainly in the unlocking operation to prevent too'violent or extensive a downward displacement of the protect the leaf and contact s rings 4 and 5.

Mo ifications in the construction herein illustrated and described may be made without departing from the scope of the invention as claimed.

What I claim is 1. In combination, a threaded socket; shell, a su port therefor, a threaded base engaged v in t e shell, a two-part lock against rotary displacement of the ment of which is .on the base and the other on the support, and means resilientlybonnecting theshell to the support for in and out movement of *theshell and base as a unitin engaging and disengaging the locking elements; K

2. In combination, a threaded socket shell,

ase in the shell, one elethe shell to the support for in and out movement of the shell and base as a unit in engaging and disengaging the lockin elements, an means for limitlng such in an out movement.

3. In combination, a threaded socket shell a support therefor, a threaded base. engaged .in the shell, a twoart lock against rotary displacement of the ase in the shell, one element of which is on the base and the other on the support, and a spring connecting the shell to the support for transitory movement of the shell toward and from the su port in engaging and disengaging the loc g elements. 4. In combination, a threaded socket shell, a support therefor, a threaded base engaged in t e shell, a twoart lock against rotary displacement of the ase in the shell, one element of which is on the baseand the other on the support, a spring connecting the shell to the support for transitory movement of the shell toward and from the support in enga ing and disenga 'ng the locking elements, and means for limiting such transitory movement comprising a In on the support projecting into a slot in t e shell.

5. In combination, a threaded socket shell, a support therefor, a threaded base engaged in t e shell,- a lock against rotary displacement of the base in the shell comprising two complementary elements each having a tooth and an inclined surface leading thereto, one of said elements being on the base and the other on the support, and a spring connecting the shell to the support for transitory movement of the shell toward and from the sup ort in enga 'n and disen a in" the teet of the lock. g g g b MEREDITH CLARK,

a su port therefor, a threaded base engaged in t e.shell, a two-part look a inst rotary displacement of the base in t e shell, one element of which is on the base and the other 'on the support, means resiliently connecting 

